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| author | Roberto Bergantinos Corpas <rbergant@redhat.com> | 2019-10-14 10:59:23 +0200 |
|---|---|---|
| committer | Steve French <stfrench@microsoft.com> | 2019-10-21 02:19:49 +0200 |
| commit | 03d9a9fe3f3aec508e485dd3dcfa1e99933b4bdb (patch) | |
| tree | 73bb8587830b41af04ab1e8d3824133cd003ee47 /fs/cifs/smb1ops.c | |
| parent | cifs: clarify comment about timestamp granularity for old servers (diff) | |
| download | linux-03d9a9fe3f3aec508e485dd3dcfa1e99933b4bdb.tar.xz linux-03d9a9fe3f3aec508e485dd3dcfa1e99933b4bdb.zip | |
CIFS: avoid using MID 0xFFFF
According to MS-CIFS specification MID 0xFFFF should not be used by the
CIFS client, but we actually do. Besides, this has proven to cause races
leading to oops between SendReceive2/cifs_demultiplex_thread. On SMB1,
MID is a 2 byte value easy to reach in CurrentMid which may conflict with
an oplock break notification request coming from server
Signed-off-by: Roberto Bergantinos Corpas <rbergant@redhat.com>
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com>
Reviewed-by: Aurelien Aptel <aaptel@suse.com>
Signed-off-by: Steve French <stfrench@microsoft.com>
CC: Stable <stable@vger.kernel.org>
Diffstat (limited to 'fs/cifs/smb1ops.c')
| -rw-r--r-- | fs/cifs/smb1ops.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/fs/cifs/smb1ops.c b/fs/cifs/smb1ops.c index b7421a096319..514810694c0f 100644 --- a/fs/cifs/smb1ops.c +++ b/fs/cifs/smb1ops.c @@ -171,6 +171,9 @@ cifs_get_next_mid(struct TCP_Server_Info *server) /* we do not want to loop forever */ last_mid = cur_mid; cur_mid++; + /* avoid 0xFFFF MID */ + if (cur_mid == 0xffff) + cur_mid++; /* * This nested loop looks more expensive than it is. |